1. Field of the Invention
The present invention relates generally to an improved magazine for a pneumatic fastener driving tool, and in particular, to an improved magazine which allows the user to easily clear a tool which has a fastener jammed in the drive track.
2. Description of the Prior Art Prior art workers have devised many types of pneumatically operated tools for driving fasteners. Patents such as U.S. Pat. No 2,983,922 which issued to Juilfs and corresponding Re. U.S. Pat. No. 26,262 describe pneumatic fastener driving tools which are characterized as having a guide body extending laterally from the pneumatic member at a forward end and including a driver extending from the pneumatic member through a drive channel in the guide body. A magazine is fixed to the underside of the pneumatic member with an open feed end extending into the guide body and having a tensioning mechanism for feeding fasteners into the drive channel.
From time to time, a fastener may become jammed within the drive track of the tool, making it necessary to remove the jammed fastener before the tool can function properly. This problem has been addressed several times in the prior art.
U.S. Pat. No. 2,733,440, which issued to Jenny, describes a fastener driving tool in which the magazine is pivotally affixed to the tool at the center of the upper side of the magazine, so it may be pivoted away from the nosepiece, making it easy to remove jammed fasteners from the drive track. U.S. Pat. No. 3,437,250, which issued to Fiedler, teaches a tool having a slidable side wall member movable to expose the interior of the magazine and drive track, although the drive track still remains partially obstructed.
U.S. Pat. No. 4,304,349, which issued to Novak et al., describes a tool having a first and second nose members which define the drive track, and first and second slidable track members which define the fastener track within the magazine. The first nose member is fixed to the tool body, while the second nose member is supported in the second track member. In order to clear a jam, both the first and second track members are retracted to separate the first and second nose members, allowing access to the drive track.
Although the prior art references all teach different methods of clearing jams from the drive track of fastener driving tools, each of these has deficiencies in terms of complexity, convenience, or ease of operation.
For example, although the device taught in U.S. Pat. No. 4,304,349 makes it easier to clear jammed fasteners from the drive track than the earlier references, the process is a two step operation in which the first track member is initially retracted, followed by the retraction of the second track member. In addition, the second track member can only be retracted a short distance, as can be seen in FIG. 13 of the patent, thus limiting the access to the drive track. Finally, as the first end of the track member is generally J shaped, it provides little support for the front plate of the tool during a drive cycle, when very large forces are applied, especially when a fastener jams against the front plate during operation of the tool.